Doppler-Resolved Spectroscopy as an Assignment Tool in the Spectrum of Singlet Methylene†

Gregory E. Hall; Anatoly V. Komissarov; Trevor J. Sears

doi:10.1021/jp0494133

Doppler-Resolved Spectroscopy as an Assignment Tool in the Spectrum of Singlet Methylene†

The Journal of Physical Chemistry A ◽

10.1021/jp0494133 ◽

2004 ◽

Vol 108 (39) ◽

pp. 7922-7927 ◽

Cited By ~ 12

Author(s):

Gregory E. Hall ◽

Anatoly V. Komissarov ◽

Trevor J. Sears

Keyword(s):

Singlet Methylene

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Singlet Methylene Removal Rate Constants from the (0,1,0) Vibrational Level: Enhancement via Complex-Mediated Vibrational Relaxation

Zeitschrift für Physikalische Chemie ◽

10.1524/zpch.2001.215.6.795 ◽

2001 ◽

Vol 215 (6) ◽

Cited By ~ 1

Author(s):

M.A. Buntine ◽

G.J. Gutsche ◽

W.S. Staker ◽

M.W. Heaven ◽

K.D. King ◽

...

Keyword(s):

Vibrational Level ◽

Rate Constants ◽

Vibrational Relaxation ◽

Flash Photolysis ◽

Laser Flash Photolysis ◽

Removal Rate ◽

Laser Flash ◽

Laser Absorption ◽

Photolysis Laser ◽

Singlet Methylene

The technique of laser flash photolysis/laser absorption has been used to obtain absolute removal rate constants for singlet methylene,

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Ab Initio Study of the Stability of the Ylide-like Intermediate Methyleneoxonium in the Reaction between Singlet Methylene and Water

Journal of the American Chemical Society ◽

10.1021/ja952771m ◽

1996 ◽

Vol 118 (23) ◽

pp. 5408-5411 ◽

Cited By ~ 33

Author(s):

Carlos Gonzalez ◽

Albeiro Restrepo-Cossio ◽

Manuel Márquez ◽

Kenneth B. Wiberg

Keyword(s):

Ab Initio ◽

Ab Initio Study ◽

The Stability ◽

Singlet Methylene

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Methylene. III. Gas phase reactions with 1-chloropropane

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1969.0146 ◽

1969 ◽

Vol 312 (1509) ◽

pp. 141-161 ◽

Cited By ~ 2

Keyword(s):

Gas Phase ◽

Rate Constants ◽

Hydrogen Abstraction ◽

The Other ◽

Gas Phase Reactions ◽

Other Hand ◽

Chlorine Substituent ◽

High Degree ◽

Singlet Methylene

The work described in this and the following paper is a continuation of that in parts I and II, devoted to elucidation of the mechanism of the reactions of methylene with chloroalkanes, with particular reference to the reactivities of singlet and triplet methylene in abstraction and insertion processes. The products of the reaction between methylene, prepared by the photolysis of ketene, and 1-chloropropane have been identified and estimated and their dependence on reactant pressures, photolysing wavelength and presence of foreign gases (oxygen and carbon monoxide) has been investigated. Both insertion and abstraction mechanisms contribute significantly to the over-all reaction, insertion being relatively much more important than with chloroethane. This type of process appears to be confined to singlet methylene. If, as seems likely, there is no insertion into C—Cl bonds under our conditions (see part IV), insertion into C2—H and C3—H bonds occurs in statistical ratio, approximately. On the other hand, the chlorine substituent reduces the probability of insertion into C—H bonds in its vicinity. As in the chloroethane system, both species of methylene show a high degree of selectivity in their abstraction reactions. We find that k S Cl / k S H >7.7, k T Cl / k T H < 0.14, where the k ’s are rate constants for abstraction, and the super- and subscripts indicate the species of methylene and the type of atom abstracted, respectively. Triplet methylene is discriminating in hydrogen abstraction from 1-C 3 H 7 Cl, the overall rates for atoms attached to C1, C2, C3 being in the ratios 2.63:1:0.

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Quantitative FM Spectroscopy at High Temperatures: The Detection of 1CH2 behind Shock Waves

Zeitschrift für Physikalische Chemie ◽

10.1524/zpch.2000.214.12.1723 ◽

2000 ◽

Vol 214 (12) ◽

Cited By ~ 7

Author(s):

G. Friedrichs ◽

H.Gg. Wagner

Keyword(s):

High Temperature ◽

Shock Waves ◽

High Temperatures ◽

Frequency Modulation ◽

Modulation Frequency ◽

Optical Power ◽

Time Resolved ◽

Signal Conversion ◽

High Modulation ◽

Singlet Methylene

The technique of time resolved frequency modulation (FM) spectroscopy has been shown to provide a very sensitive means to detect small radicals behind shock waves. Features of high temperature FM spectroscopy behind shock waves will be discussed and a general signal conversion procedure to carry out quantitative concentration measurements will be presented.Using a high modulation frequency, a high modulation index and high total optical power, singlet methylene radicals (α

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